1. Field of the Invention
The invention relates to a brake device and to a braking method for a motor vehicle.
2. Description of the Related Art
In hydraulic brake devices, it is generally known that the force/travel characteristic curve is influenced by the geometric dimensions of the brake device. External influences, such as, wet brake disks, changes to the brake linings, trailer mode and fading also influence the vehicle deceleration that can be brought about by the pedal activation. In brake systems with a pedal simulator, a force/travel characteristic curve is generated electronically by a control unit. In this context, a failure to couple frequently occurs under the external influences mentioned above.
EP 1 138 564 A2 describes an electromechanical vehicle brake system with electronic transmission of a braking process, triggered by a brake pedal, to a brake on the vehicle wheel. This brake system has a slip control function when wheel slip occurs and brings about activation of the brakes that differs from the activation of the brake pedal. A reaction behavior can be generated when such a slip control function is activated at the brake pedal such as is otherwise customary in a hydraulic vehicle brake system.
In the described electromechanical vehicle brake system, this reaction behavior can be generated in what is referred to as a pedal simulator, namely a vibrator or a piezo-element. In this context, the generation of the reaction behavior optionally can be prevented and the reaction behavior that corresponds to an active slip control function in a hydraulic brake system can be amplified or attenuated in comparison to the latter.
The object of the invention is to provide a brake device and a braking method for a motor vehicle that give the driver a natural brake pedal sensation and permit coupling between the force/travel characteristic curve of the brake device and prevailing ambient influences.